Using the CentOS Errata Website
When security errata reports are released, they are published on the CentOS Errata website available at http://www.redhat.com/security/. From this page, select the product and version for your system, and then select security at the top of the page to display only Community Enterprise Linux Security Advisories. If the synopsis of one of the advisories describes a package used on your system, click on the synopsis for more details.
The details page describes the security exploit and any special instructions that must be performed in addition to updating the package to fix the security hole.
To download the updated package(s), click on the link to login to CentOS Network, click the package name(s) and save to the hard drive. It is highly recommended that you create a new directory, such as /tmp/updates, and save all the downloaded packages to it.